大鼠全脑缺血再灌后海马CA1区Bax蛋白和bcl-2表达及EGb761的保护作用

目的观察EGb761对大鼠全脑缺血再灌注后bcl-2和Bax表达的影响,以初步探讨EGb761对脑缺血损伤保护的分子机制。方法采用Pulsinelli四血管闭塞法略作改动制备大鼠弥漫性全脑缺血模型。将健康SD大鼠72只随机分为缺血再灌注组（IR组）、假手术组（SAM组）和EGb761预处理组（EGb组）,采用免疫组化SABC法和原位杂交方法对海马CA1区各再灌注时间点的Bax蛋白和bcl-2 mRNA进行检测。结果 Bax蛋白免疫组化和bcl-2 mRNA原位杂交检测可见阳性信号以再灌注24h最强,之后下降,以72h下降最明显（P〈0.05）。IR组Bax表达较SAM组明显增强（P〈0.05）,而EGb组Bax阳性信号较对应时间点的IR组明显减弱（P〈0.05）,EGb组bcl-2 mRNA阳性信号较对应时间点的IR组明显增强（P〈0.05）。结论 bcl-2和Bax是参与神经细胞调亡的重要调控基因,EGb761对脑缺血再灌注后的神经细胞具有显著的保护作用,其机制可能与上调bcl-2基因和下调Bax蛋白表达,从而抑制神经细胞凋亡有关。

Expression of Bax and bcl-2 after Cerebral Ischemia-Reperfusion in Rat Hippocampal CA1 Area and Protective Effect of EGb761

Objective To investigate the expression of bcl-2 and Bax and the protective effect of EGb761 after cerebral ischemia-reperfusion injury in rats.Methods Healthy SD rats were randomly divided into three groups： ischemia-reperfusion group（IR group）,sham operated group（SHAM group） and EGb761 pre-treated group（EGb group）.bcl-2 mRNA was detected by in situ hybridization（ISH） and Bax protein was detected by immunohistochemistry staining after 24h,48h and 72h of reperfusion.Results The positive signals of both bcl-2 mRNA and Bax protein in IR group were significantly increased（P〈0.05） and reached a peak at 24h as compared to SHAM group;compared with IR group,the expression of bcl-2 mRNA was obviously increased（P〈0.05） and the positive signal of Bax protein was remarkably decreased（P〈0.05） in EGb group.Conclusion The antiapoptotic bcl-2 gene and proapoptotic Bax gene perhaps are important regulative genes in neuronal apoptotic process.EGb761 has highly neuroprotective effects against the delayed neuronal death,and its possible protective mechanisms were closely related to up-regulation of bcl-2 gene and down-regulation of Bax gene.